Despite her many achievements as a scientist and mathematician, Gabrielle-Emilie, marquise du Châtelet is most famous for being the lover of François Marie Arouet, who is best known as Voltaire (1694-1778). This fact is unfortunate because Châtelet was a highly talented thinker in her own right and would probably have become much more famous if she had not been a woman in eighteenth-century France.

She was born Gabrielle-Emilie le Tonnelier de Breteuil in Paris on December 17, 1706. Her aristocratic upbringing allowed her an opportunity to enjoy an education beyond the reach of most girls, and she studied science, music, and literature with a series of tutors. At 19, Gabrielle-Emilie married the marquis du Châtelet and was thenceforth known as the marquise du Châtelet.

The couple had three children but her marriage to the marquis did not stop the marquise from seeking romance elsewhere—in the arms of Voltaire, who became her lover in 1733. Voltaire encouraged her to study mathematics, which she did under the tutelage of the scientist Pierre-Louis Moreau de Maupertuis (1698-1759). In 1734 Voltaire, facing trouble for his outspoken criticism of the French royal house, moved in with the marquise and, as a result, their chateau became a magnet for many of the era's great minds. During this time, Châtelet assisted Voltaire in a study on Newton (1642-1727) called Elements of Newton's Philosophy (1738).

Châtelet became intrigued with a number of scientific questions, among them the nature of combustion. Combustion, a much-debated topic at the time, was at the subject of a 1737 contest sponsored by the Académie Royale des Sciences, for which Châtelet submitted a paper. She rightly rejected the prevailing phlogiston theory, arguing correctly that heat was not a substance and, with even more prescience, suggested that light and heat are related. Châtelet did not win, but the fact that Leonhard Euler (1707-1783) walked off with the prize suggests the kind of competition she faced.

Châtelet also translated Newton's Principia mathematica into French and might have accomplished many more things. She became pregnant again at the age of 42, however, and died of a puerperal fever shortly after giving birth to a daughter on September 4, 1749.